Building an ADU in Salt Lake City

What you can build here

Section 21A.40.200 of the city code allows "a single ADU" on a property where the land use tables in Chapter 21A.33 permit it. The ADU can be internal (inside the house), attached or detached. There is no minimum lot size, and an ADU doesn't count toward the density allowed in the zone.

An ADU can't become a separate principal use: the code says it "cannot be converted to another principal use." It may be converted to another accessory use allowed in the zone, and it may include a home occupation.

Utah law makes internal ADUs a permitted use in primarily residential areas statewide. See our Utah ADU law page for what the state requires. [1][3]

Size, height and setbacks

Size. A detached ADU may not exceed 1,000 square feet of gross floor area. Stairs to a second-level ADU, lofts under 7 feet high, and storage basements with no internal connection don't count. An internal ADU has no maximum size if the building meets the zone's standards. ADUs also count toward the zone's building and yard coverage limits.

Height. A detached ADU can be 17 feet tall. It can go up to 24 feet with a pitched roof or 20 feet with a flat roof if you add one foot of side and rear setback for each foot above 17. An ADU fully within the lot's buildable area can be as tall as the main house is allowed to be. An internal ADU follows the main building's height rules.

Location and setbacks. A detached ADU can't go in the front yard. In an interior side yard it must sit behind the back of the house; on a corner side it can't be closer to the street than the house (unless the lot is under 50 feet wide). It must be at least 3 feet from rear and side lot lines, and the smaller of 20% of the lot width or 10 feet from a corner side lot line.

Design details. Rooftop patios aren't allowed on detached ADUs, and decks more than 2 feet above grade are allowed only if the ADU is within the lot's buildable area. Second-story windows facing a side or rear lot line are limited unless, for example, they are clerestory windows or at least 10 feet from the line. A detached ADU within 15 feet of a public alley needs a shielded exterior light and a 4-foot path from the alley to its entrance. [1]

Parking

You can't reduce the main home's parking below the code minimum to make room for an ADU. The ADU needs one parking stall, except when:

• the property is in a zone with no minimum off-street parking requirement;
• it already has at least one stall above the minimum for the main use;
• it is within a quarter mile of a public transit stop; or
• it is within a half mile of a city-designated bicycle lane or path.

State law caps what Utah cities can require: one extra space for an internal ADU, and, for detached ADUs in larger cities, one space under 650 square feet or two at 650 or more. Salt Lake City's one-stall rule is within those limits. [1][3][4]

Owner occupancy and the restrictive covenant

The owner must live on the property. The owner can be someone listed on the recorded deed, a relative of that person by blood, marriage or adoption, or the trustor of a family trust that owns the property. Owner occupancy isn't required if the main use is a duplex, multifamily building or nonresidential use, during a temporary absence of three years or less (such as military service or a job assignment), or if the owner is in a hospital, nursing home or similar care facility.

Every ADU must have a restrictive covenant recorded against the property. It describes the house and ADU and parking, states that neither can be a short-term rental, and lets the city inspect to confirm the use. Utah law lets cities bar renting an internal ADU in a home that isn't the owner's primary residence, and lets larger cities require the owner of a lot with a detached ADU to live in the house or the ADU. [1][3][4]

Fees

Salt Lake City doesn't publish a single ADU fee. Expect:

• Building permit and plan review fees, which you can estimate with the city's fee calculation tools and Consolidated Fee Schedule, linked from the Building Permits page.
• Impact fees for each new dwelling unit, calculated on the city's impact fee worksheet. Stormwater impact fees are figured separately by Public Utilities.
• A rental business license if you rent the ADU. The city says all residential rental properties need one, and landlord/tenant program participants can get per-unit fees discounted by up to 95%.

Separate trade permits carry their own fees. See our ADU cost guide for whole-project budgeting. [5][6][7][8]

Garage conversions

An existing accessory building, such as a detached garage, can be converted to an ADU and keep its existing setbacks, and a conversion is allowed even if the building is taller than the ADU height limit. Any expansion, including a second story, must meet the ADU setback and height rules.

The city's pre-approved plans include a detached garage conversion and a second-story detached garage conversion. A garage conversion can't drop the main home's parking below the code minimum. See our garage conversion guide. [1][9]

Renting it out

You can rent an ADU long term, but not as a short-term rental: the code says an ADU "shall not be rented as a short term rental," and the recorded covenant applies that to the main house too. If you need a business license to rent the ADU, you must enroll in the landlord/tenant program before the city issues the zoning certificate. [1][7]

Pre-approved plans and other help

Building Services lists pre-approved standard plans from private design firms; you contact the firm to use one. The city says the plans were reviewed "for minimum compliance with applicable building codes" and that a site review is still needed for a permit.

For general steps, see our ADU permit process guide and guide to hiring ADU help. [9]

Permit steps in Salt Lake City

1. Check your zoning with the Planning Counter

   ADUs are allowed where the land use tables in Chapter 21A.33 permit them. For new structures and additions, the city says the Planning Counter should be your first contact: (801) 535-7700, Room 215 of the City & County Building, Monday to Friday 8 a.m. to 5 p.m. [1][5]

2. Hire a licensed contractor

   A contractor's license is required for an ADU building permit unless there is no construction or the work is under $7,000 with no mechanical, electrical or plumbing work. The state owner-builder certification can't be used for an ADU. See Contractor Required for an ADU. [2]

3. Pick a design or a pre-approved plan

   Design to the ADU standards in Section 21A.40.200, or choose one of the city's pre-approved standard plans. A site review is still required for a building permit. [1][9]

4. Apply in the Citizen Access Portal and upload plans to ProjectDox

   Register at slcpermits.com, choose the Building tab and a residential permit type, then upload your plans in ProjectDox when you get the invitation email. Trade permits are separate. [8]

5. Pass prescreen, pay fees and complete plan review

   After prescreen you pay fee balances and plans go to building and fire code review. Fill out the city's impact fee worksheet for the new dwelling unit. [5][6][10]

6. Record the restrictive covenant

   Every ADU needs a restrictive covenant, on a city attorney form, recorded with the Salt Lake County Recorder. A copy goes to the Planning Division before the ADU's final inspection. [1]

7. Get inspections, a zoning certificate and a certificate of occupancy

   The certificate of occupancy won't be issued until a zoning certificate is issued. If you need a business license to rent the ADU, you must enroll in the landlord/tenant program first. [1]

Pre-approved and sample plans

• Pre-Approved ADU Standard Plans

  Plans pre-approved by Building Code staff, including a 650 sq ft one-bedroom unit, a 775 sq ft two-bedroom unit and detached garage conversions; you contact the design firm to use one. [9]

Who to call

• Planning Counter (Planning Division)

  Zoning and ADU questions; first stop for new structures and additions. Email zoning@slc.gov

  801-535-7700

  City & County Building, 451 South State Street, Room 215, Salt Lake City, UT 84111

  [5][10]

• Building Services, Permit Processing

  Building permit applications and status

  (801) 535-7968

  [10]

• Building Services, General Building Code Questions

  Building code questions before and during plan review

  (801) 535-7155

  [10]

• Inspection Scheduling and One-Stop Development Phone Tree

  Inspections and certificate of occupancy information

  801-535-6000

  [5]

• Public Utilities Development Services

  Water, sewer and stormwater questions, including stormwater impact fees

  (801) 483-6727

  [6][10]

Questions people ask